The present invention relates to fluid conduits such as hoses and pipes.
Fluid conduits are used in a wide variety of applications to convey fluids between different locations. Perhaps one of the widest uses is the provision of pipes to convey water to commercial and residential establishments but pipes are also used to convey other fluids such as fuel oils, gasoline or other chemical substances.
The conduits are often installed in relatively hostile environments in which the fluids conveyed can be subject to temperatures that makes handling of the fluids difficult. Typically, in water distribution systems, there is a danger that the ambient temperature will drop below freezing and result in a blockage or bursting of the distribution pipe. In areas where this is likely to occur, the pipe may be buried beneath the frost line determined for that region, which may be over one meter below the ground level. This is of course relatively expensive and inhibits access to the pipe for routine maintenance and inspection. Moreover in some environments, it is not practical to bury the conduit due to ground conditions and essentially the pipe must remain exposed on the ground.
In Canadian Patent 2,019,590, a system is described in which a self regulating electrical heating cable is installed within a pipe so that heat may be supplied to the water within the pipe to prevent freezing. This arrangement facilitates the use of insulation around the pipe to reduce energy consumption and has enjoyed wide spread commercial success.
In some installations it is not practical to install a heating cable within the pipe. If the conduit is intended to carry combustibles then it is preferable to separate the heating element from the fluid itself. In other environments, the pressure of the fluid within the conduit makes the use of the internal heating cable impractical.
It is well known to retrofit a heating cable to the outside of a pipe by wrapping the cables spirally about the pipe. However, this arrangement is relatively inefficient in that heat transfer depends upon the contact between the heating element and the outer surface of the pipe and this cannot be assured with a manual wrapping of the cable about the pipe. Moreover, the cable remains vulnerable to external forces that may damage the cable or present a safety risk.
It is therefore an object to the present invention to provide a fluid conduit in which the above disadvantages are obviated or mitigated.
In general terms, the present invention provides a fluid conduit having a peripheral wall defining a fluid passage extending along a longitudinal access, a heating element in contact with the peripheral wall and extending parallel to the longitudinal access and a jacket entrained about the peripheral wall and heating element to maintain the heating element in contact with the peripheral wall.
Preferably, the heating element is a smaller diameter than the fluid passage and a void is created between the jacket and peripheral wall.
As a further preference, an insulating sleeve is positioned over the jacket to inhibit heat transfer from the heating element.